1. Field of the Invention
The present invention relates generally to a washing machine having at least one balancer, and more particularly to a washing machine having at least one balancer that increases durability by reinforcing strength and that is installed on a rotating tub in a convenient way.
2. Description of the Related Art
In general, washing machines do the laundry by spinning a spin tub containing the laundry by driving the spin tub with a driving motor. In a washing process, the spin tub is spun forward and backward at a low speed. In a dehydrating process, the spin tub is spun in one direction at a high speed.
When the spin tub is spun at a high speed in the dehydrating process, if the laundry leans to one side without uniform distribution in the spin tub or if the laundry leans to one side by an abrupt acceleration of the spin tub in the early stage of the dehydrating process, the spin tub undergoes a misalignment between the center of gravity and the center of rotation, which thus causes noise and vibration. The repetition of this phenomenon causes parts, such as a spin tub and its rotating shaft, a driving motor, etc., to break or to undergo a reduced life span.
Particularly, a drum type washing machine has a structure in which the spin tub containing laundry is horizontally disposed, and when the spin tub is spun at a high speed when the laundry is collected on the bottom of the spin tub by gravity in the dehydrating process, the spin tub undergoes a misalignment between the center of gravity and the center of rotation, thus resulting in a high possibility of causing excess noise and vibration.
Thus, the drum type washing machine is typically provided with at least one balancer for maintaining a dynamic balance of the spin tub. A balancer may also be applied to an upright type washing machine in which the spin tub is vertically installed.
An example of a washing machine having ball balancers is disclosed in Korean Patent Publication No. 1999-0038279. The ball balancers of a conventional washing machine include racers installed on the top and the bottom of a spin tub in order to maintain a dynamic balance when the spin tub is spun at a high speed, and steel balls and viscous oil are disposed within the racers to freely move in the racers.
Thus, when the spin tub is spun without maintaining a dynamic balance due to an unbalanced eccentric structure of the spin tub itself and lopsided distribution of the laundry in the spin tub, the steel balls compensate for this imbalance, and thus the spin tub can maintain the dynamic balance.
However, the ball balancers of the conventional washing machine have a structure in which upper and lower plates formed of plastic by injection molding are fused to each other, and a plurality of steel balls are disposed between the fused plates to make a circular motion, so that the ball balancers are continuously supplied with centrifugal force that is generated when the steel balls make a circular motion, and thus are deformed at walls thereof, which reduces the life span of the balancer.
Further, the ball balancers of the conventional washing machine do not have a means for guiding the ball balancers to be installed on the spin tub in place, so that it takes time to assemble the balancers to the spin tub.
In addition, the ball balancers of the conventional washing machine have a structure in which a racer includes upper and lower plates fused to each other, so that fusion scraps generated during fusion fall down both inwardly and outwardly of the racer. The fusion scraps that fall down inwardly of the racer prevent motion of the balls in the racer, and simultaneously result in generating vibration and noise.